LOCATION ZAFRA OK+AR
Established Series
Rev. JWF:LBW
02/2018
ZAFRA SERIES
The Zafra series consists of moderately deep, well drained, moderately permeable soils that formed in loamy colluvial sediments that weathered from interbedded sandstone and shale of Pennsylvanian age. These soils are on very gently sloping to moderately steep sideslopes and footslopes of the Ouachita Mountains. Water runs off the surface medium to rapidly fast. Slopes range from 1 to 20 percent.
TAXONOMIC CLASS: Loamy-skeletal, siliceous, semiactive, thermic Typic Hapludults
TYPICAL PEDON: Zafra loam, forested.
(Colors are for moist soil unless otherwise stated.)
A--0 to 4 inches; dark grayish brown (10YR 4/2) loam; weak fine granular structure; friable; many fine roots; about 5 percent hard fragments of sandstone 1/4 to 2 inch diameter; moderately acid; clear smooth boundary. (2 to 6 inches thick)
E--4 to 10 inches; yellowish brown (10YR 5/4) loam; weak fine granular structure; friable; about 5 percent hard fragments of sandstone 1/4 to 2 inch diameter; strongly acid; clear smooth boundary. (0 to 8 inches thick)
BE--10 to 15 inches; strong brown (7.5YR 5/6) gravelly loam; weak fine subangular blocky structure; friable; about 15 percent fragments of sandstone 1/4 to 3 inch diameter; very strongly acid; clear smooth boundary. (3 to 8 inches thick)
Bt1--15 to 26 inches; yellowish red (5YR 5/6) very gravelly loam; weak medium subangular blocky structure; friable; patchy thin clay films on fragments and faces of peds; about 40 percent hard and soft fragments of sandstone 1/4 to 3 inch diameter; very strongly acid; gradual irregular boundary. (8 to 22 inches thick)
Bt2--26 to 38 inches; yellowish red (5YR 5/6) very gravelly sandy clay loam; weak medium subangular blocky structure; friable; patchy thin clay films on fragments and faces of peds; about 60 percent hard and soft sandstone fragments, a few crush to fine sandy loam; very strongly acid; gradual irregular boundary. (0 to 12 inches thick)
Cr--38 to 45 inches; alternating layers of brown, red, and yellow sandstone and lenses of reddish shale; sandstone crushes to fine sandy loam; shale crushes to silty clay loam; many hard sandstone fragments 1/4 to 4 inch diameter; very strongly acid; clear irregular boundary. (4 to 19 inches thick)
R--45 to 55 inches; hard sandstone interbedded with soft sandstone and lenses of shale. The strata are tilted 20 to 60 degrees from horizontal.
TYPE LOCATION: McCurtain County, Oklahoma. About 0.8 mile east of the State Game Preserve road. About 350 feet north and 350 feet west of the southeast corner of Sec. 32, T. 25 N., R. 24 E.
RANGE IN CHARACTERISTICS: Solum thickness ranges from 20 to 56 inches and depth to hard rock ranges from 25 to 60 inches. The coarse fragments are angular pieces of hard and soft sandstone with minor amounts of shale.
The A horizon is very dark grayish brown (10YR 3/2), dark brown (10YR 3/3, 4/3), or dark grayish brown (10YR 4/2). It is fine sandy loam, loam, or very fine sandy loam and ranges from medium acid through strongly acid. Coarse fragments more than 3 inches diameter make up 0 to 2 percent of the volume, and those less than 3 inches diameter make up 5 to 20 percent.
The E horizon is yellowish brown (10YR 5/4), brown (10YR 5/3), pale brown (10YR 6/3), light yellowish brown (10YR 6/4), strong brown (7.5YR 5/6), or reddish yellow (7.5YR 6/6). Texture, reaction, and coarse fragments are similar to that of the A horizon.
The BE horizon is yellowish brown (10YR 5/4, 5/6, 5/8), strong brown (7.5YR 5/6, 5/8), yellowish red (5YR 5/6, 5/8), or reddish yellow (5YR 6/6, 6/8). It is loam or gravelly loam. Coarse fragments larger than 3 inches diameter make up 0 to 2 percent of the volume, and those smaller than 3 inches make up 10 to 25 percent of the volume.
The Bt1 horizon is brown (7.5YR 4/4), strong brown (7.5YR 5/6, 5/8), yellowish red (5YR 4/6, 4/8, 5/6, 5/8), or red (2.5YR 4/6, 4/8, 5/6, 5/8). It is gravelly or very gravelly loam, gravelly or very gravelly clay loam, gravelly or very gravelly sandy clay loam. Coarse fragments larger than 3 inches diameter make up 0 to 5 percent of the volume, and those less than 3 inches diameter make up 35 to 70 percent of the volume.
The Bt2 horizon is yellowish red (5YR 4/6, 4/8, 5/6, 5/8) or strong brown (7.5YR 5/6, 5/8). Texture and coarse fragments are similar to those in the B2t horizon and includes gravelly and very gravelly sandy laom.
The Cr horizon is shades of red, brown, and yellow soft sandstone with thin alternating beds of shale and hard sandstone.
The R layer is hard sandstone with thin layers of shale and soft sandstone tilted at 20 to 60 degrees from horizontal.
COMPETING SERIES: These are the
Apison,
Bigfork,
Bodine,
Cahaba,
Durham,
Granville,
Hartsells,
Holston,
Kalmia,
Lillington,
Lockhart,
Maxton,
Mountainburg,
Ruston,
Saffell,
Shermore,
Sherwood, and Sublinga series. Apison, Cahaba, Durham, Granville, Hartsells, Kalmia, Maxton, Shermore, and Sherwood soils have less than 35 percent fragments larger than 2 mm in the Bt horizons. Bigfork soils are underlain by hard chert. Bodine, Holston, and Ruston soils have sola thicker than 60 inches and in addition Holston and Ruston soils lack coarse fragments. Lillington soils have sola more than 60 inches thick. Lockhart soils have mixed mineralogy and the coarse fragments are primarily feldspar. Mountainburg soils have sola less than 20 inches over hard rock. Saffell and Sublinga soils lack bedrock within 60 inches. In addition, Saffell soils have Bt horizons with more than 35 percent fragments of quartz, chert, or hard siliceous materials.
GEOGRAPHIC SETTING: Zafra soils are on very gently sloping to moderately steep sideslopes and footslopes of the Ouachita Mountains. Slopes range from 1 to 20 percent. Mean annual precipitation is 40 to 50 inches and is evenly distributed throughout the year. Mean annual temperature ranges from 59 degrees to 66 degrees F. Thornthwaite annual P-E indices range from 64 to 76
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing
Shermore and
Sherwood series and the
Carnasaw,
Clebit,
Pickens,
Pirum, and
Stapp series. Shermore and Sherwood soils occur on similar positions of the landscape. Carnasaw soils occur on similar positions of the landscape and they have fine control sections. Clebit and Pickens soils occur on ridgecrests and have solums 10 to 20 inches thick. Pirum soils occur on similar positions of the landscape and they have less than 35 percent fragments of shale or sandstone. Stapp soils occur on concave areas and have fine control sections.
Drainage and Permeability: Zafra soils are well drained. Runoff is medium to rapid and permeability is moderate.
USE AND VEGETATION: Principal use is woodland with some areas used for pasture. Forest vegetation includes shortleaf pine, red oak, post oak, sweetgum, and hickory.
DISTRIBUTION AND EXTENT: Ouachita Mountains of Oklahoma and Arkansas. The series is of moderate extent.
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: MORGANTOWN, WEST VIRGINIA
SERIES ESTABLISHED: McCurtain County, Oklahoma; 1970.
REMARKS: Zafra soils would have been classified in the Red-Yellow Podzolic great soil group.
National Cooperative Soil Survey
U.S.A.